Gas-main



(No Model.)

J. H. MOBLROY.

GAS MAIN.

Patented Oct. 6, 1885.

INVENTOR,

ATTORNEY.

N. PETERS4 Mmmm-Nunn.' wmv-gum D. C

UNITED STATES PATENT OFFICE.

JOHN H. MOELROY, OF PITTSBURG, PENNSYLVANIA. I

SPECIFICATION forming part of Letters Patent No.327,703, dated October 6, 1885.

Serial No. 174,854. (No model.)

T0 all whom it may concern:

Beit known that I, JOHN H. MCELROY, a citizen of the United States, residing at Pitts burg, in the county of Allegheny and State of Pennsylvania, have invented an Improvement in GasMains, or a new and improved means of preventing accidents from gas which may have escaped from gas-mains underneath the surface of the ground, and I do hereby declare that the following is a clear and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

lThe object of my invention is to secure a rapid and free discharge into the atmosphere,

at a safe distance above the surface of the ground, of all gas which may leak from gasmains, and thus prevent accidents from eXplosions of gas which might otherwise collect in cellars, sewers, or other adjacent places capable of receiving and holding gas, and also to determine whether or not a 'leak from a main exists, and if so its locality, in order to readily stop the same.

To carry my invention into effect, I place upon the upper side of the main E, when in position, and running the entire length thereof, sections of what is known as U shaped l pipe, made of terra-cotta or any other suitable substance, united by means of common bowlvjoints, and held in position upon the main by ramming of the earth at each side. It is intended that the U-shaped pipe A, or conduit for the gas, shall be chipped out at each joint a of the main, so as to allow it to sit down thereon, but not so close as to prevent any gas which may leak from the under sideof the main from passing around and into the U-shaped pipe. At convenient intervals standpipes B are to be inserted into the U- shaped pipe in order to carry the gas to a safe point above the surface of the ground, and by applying a lighted match at the mouth of any of these stand-pipes a leak, if any, can be detected. Inside of the U-shaped pipe or conduit are to be placed diaphragms C, made from clay or any convenient material, at distances corresponding with the stand-pipes, so as to determine or ascertain the locality of a leak. Finally, I cover the entire length of the U-shaped pipe with tar-paper D, of sufficient width to pass down and over the entire main and its joints.

Reference is to be had to the accompanying drawings, which are intended to form a part of this specification.

Figure l is a longitudinal View, partly in section, showing the U shaped pipe or conduit in position, with standpipes for conducting off leakage A. Fig. 2 is a sectional View taken on the line m w of Fig. l. Fig. 3 is a similar view taken on the line y y. Fig. 4 is a perspective view showing one end of the U shaped pipe.

The letter A represents the U-shaped pipe or conduit for the leakage; B, the stand-pipe to carry the gas into the open air; C, the diaphragm inside the U-shaped pipe, and D the tar-paper enveloping both main and U -shaped pipe.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- In a system of pipes for conveying gas from a leak in any part'of a main into the open air by means of the U-shaped pipe A, in combination with the stand-pipe B, the diaphragm O, and the tar-paper D, substantially as herein set forth.

JOHN H. MCELROY.

A. H. CLARKE, W. H. MCGLELLAND. 

